Methods of inhibiting growth hormone effects

ABSTRACT

A method of inhibiting effects of growth hormone comprising administering to a human in need thereof an effective amount of a compound having the formula ##STR1## wherein R 1  and R 3  are independently hydrogen, --CH 3 , ##STR2##  wherein Ar is optionally substituted phenyl; R 2  is selected from the group consisting of pyrrolidine, hexamethyleneamino, and piperidino; or a pharmaceutically accepatable salt of solvate thereof.

BACKGROUND OF THE INVENTION

Recent research concerning the effects of sex hormones on growth hormone secretion in males indicates that the stimulatory effect of testosterone upon the somatotropic axis is predicated upon its ability to be aromatized to estradiol. (Weissberger, J. Clin. Endocrin., 76, 1993, 1407; Metzger, J. Clin. Endocrin., 76, 1993, 1147). For pre-pubertal, pubertal and adult males, it has been demonstrated that endogenous estrogens rather than androgens play a dominant role in regulating growth hormone secretions. (Caruso-Nicoletti, J. Clin. Endocrin. , 61, 1985, 896; Ho, J. Clin. Endocrin., 64, 1987, 51; see also references above) It has recently been reported that the antiestrogen tamoxifen blocks the estradiol induced surge in growth hormone secretion in both adult and adolescent males. (Weissberger, J. Clin. Endocrin., 76, 1993, 1407; Metzger, J. Clin. Endocrin., 79, 1994, 513).

Current treatments for disorders associated with an excess of growth hormone are primarily restricted to surgical removal of all or part of the pituitary or irradiation thereof. One alternative is treatment with bromocriptine mesylate, a dopaminergic agonist, but side effects such as nausea, vomiting, postural hypotension, "cardiovascular collapse", visual and auditory hallucinations, and cutaneous livedo reticularis are problematic.

SUMMARY OF THE INVENTION

This invention provides methods for inhibiting growth hormone effects comprising administering to a human in need thereof an effective amount of a compound of formula I ##STR3## wherein R¹ and R³ are independently hydrogen, --CH₃, ##STR4## wherein Ar is optionally substituted phenyl; R² is selected from the group consisting of pyrrolidino, hexamethyleneimino, and piperidino; and pharmaceutically acceptable salts and solyates thereof.

DETAILED DESCRIPTION OF THE INVENTION

The current invention concerns the discovery that a select group of 2-phenyl-3-aroylbenzothiophenes (benzothiophenes), those of formula I, are useful for inhibiting growth hormone effects when present in elevated levels. Such effects include gigantism and acromegaly, and the delitorious effects on microvascular tissues, such as the retina.

The methods of use provided by this invention are practiced by administering to a human in need thereof a dose of a compound of formula I or a pharmaceutically acceptable salt or solvate thereof, that is effective to inhibit the effects of growth hormone. The term "inhibit" includes its generally accepted meaning which includes prohibiting, preventing, restraining, and slowing, stopping or reversing. As such, the present method includes both medical therapeutic and/or prophylactic administration, as appropriate.

Raloxifene, a compound of this invention wherein it is the hydrochloride salt of a compound of formula 1, R¹ and R³ are hydrogen and R² is 1-piperidinyl, is a nuclear regulatory molecule. Raloxifene has been shown to bind to the estrogen receptor and was originally thought to be a molecule whose function and pharmacology was that of an anti-estrogen in that it blocked the ability of estrogen to activate uterine tissue and estrogen dependent breast cancers. Indeed, raloxifene does block the action of estrogen in some cells; however in other cell types, raloxifene activates the same genes as estrogen does and displays the same pharmacology, e.g., osteoporosis, hyperlipidemia. As a result, raloxifene has been referred to as an anti-estrogen with mixed agonist-antagonist properties. The unique profile which raloxifene displays and differs from that of estrogen is now thought to be due to the unique activation and/or suppression of various gene functions by the raloxifene-estrogen receptor complex as opposed to the activation and/or suppression of genes by the estrogen-estrogen receptor complex. Therefore, although raloxifene and estrogen utilize and compete for the same receptor, the pharmacological outcome from gene regulation of the two is not easily predicted and is unique to each. As such, it is possible that raloxifene would also benefit a patient who has lower than normal levels of growth hormone.

Generally, the compound is formulated with common excipients, diluents or carriers, and compressed into tablets, or formulated as elixirs or solutions for convenient oral administration, or administered by the intramuscular or intravenous routes. The compounds can be administered transdermally, and may be formulated as sustained release dosage forms and the like.

The compounds used in the methods of the current invention can be made according to established procedures, such as those detailed in U.S. Pat. Nos. 4,133,814, 4,418,068, and 4,380,635 all of which are incorporated by reference herein. In general, the process starts with a benzo[b]thiophene having a 6-hydroxyl group and a 2-(4-hydroxyphenyl) group. The starting compound is protected, acylated, and deprotected to form the formula I compounds. Examples of the preparation of such compounds are provided in the U.S. patents discussed above. Optionally substituted phenyl includes phenyl and phenyl substituted once or twice with C₁ -C₆ alkyl, C₁ -C₄ alkoxy, hydroxy, nitro, chloro, fluoro, or tri(chloro or fluoro)methyl.

The compounds used in the methods of this invention form pharmaceutically acceptable acid and base addition salts with a wide variety of organic and inorganic acids and bases and include the physiologically acceptable salts which are often used in pharmaceutical chemistry. Such salts are also part of this invention. Typical inorganic acids used to form such salts include hydrochloric, hydrobromic, hydroiodic, nitric, sulfuric, phosphoric, hypophosphoric and the like. Salts derived from organic acids, such as aliphatic mono and dicarboxylic acids, phenyl substituted alkanoic acids, hydroxyalkanoic and hydroxyalkandioic acids, aromatic acids, aliphatic and aromatic sulfonic acids, may also be used. Such pharmaceutically acceptable salts thus include acetate, phenylacetate, trifluoroacetate, acrylate, ascorbate, benzoate, chlorobenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, methylbenzoate, o-acetoxybenzoate, naphthalene-2-benzoate, bromide, isobutyrate, phenylbutyrate, β-hydroxybutyrate, butyne-1,4-dioate, hexyne-1,4-dioate, caprate, caprylate, chloride, cinnamate, titrate, formate, fumarate, glycollate, heptanoate, hippurate, lactate, malate, maleate, hydroxymaleate, malonate, mandelate, mesylate, nicotinate, isonicotinate, nitrate, oxalate, phthalate, teraphthalate, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, propiolate, propionate, phenylpropionate, salicylate, sebacate, succinate, suberate, sulfate, bisulfate, pyrosulfate, sulfite, bisulfite, sulfonate, benzene-sulfonate, p-bromophenylsulfonate, chlorobenzenesulfonate, ethanesulfonate, 2-hydroxyethanesulfonate, methanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate, p-toluenesulfonate, xylenesulfonate, tartarate, and the like. A preferred salt is the hydrochloride salt.

The pharmaceutically acceptable acid addition salts are typically formed by reacting a compound of formula I with an equimolar or excess amount of acid. The reactants are generally combined in a mutual solvent such as diethyl ether or benzene. The salt normally precipitates out of solution within about one hour to 10 days and can be isolated by filtration or the solvent can be stripped off by conventional means.

Bases commonly used for formation of salts include ammonium hydroxide and alkali and alkaline earth metal hydroxides, carbonates, as well as aliphatic and primary, secondary and tertiary amines, aliphatic diamines. Bases especially useful in the preparation of addition salts include ammonium hydroxide, potassium carbonate, methylamine, diethylamine, ethylene diamine and cyclohexylamine.

The pharmaceutically acceptable salts generally have enhanced solubility characteristics compared to the compound from which they are derived, and thus are often more amenable to formulation as liquids or emulsions.

Pharmaceutical formulations can be prepared by procedures known in the art. For example, the compounds can be formulated with common excipients, diluents, or carriers, and formed into tablets, capsules, suspensions, powders, and the like. Examples of excipients, diluents, and carriers that are suitable for such formulations include the following: fillers and extenders such as starch, sugars, mannitol, and silicic derivatives; binding agents such as carboxymethyl cellulose and other cellulose derivatives, alginates, gelatin, and polyvinyl pyrrolidone; moisturizing agents such as glycerol; disintegrating agents such as calcium carbonate and sodium bicarbonate; agents for retarding dissolution such as paraffin; resorption accelerators such as quaternary ammonium compounds; surface active agents such as cetyl alcohol, glycerol monostearate; adsorptive carriers such as kaolin and bentonite; and lubricants such as talc, calcium and magnesium stearate, and solid polyethyl glycols.

The compounds can also be formulated as elixirs or solutions for convenient oral administration or as solutions appropriate for parenteral administration, for instance by intramuscular, subcutaneous or intravenous routes. Additionally, the compounds are well suited to formulation as sustained release dosage forms and the like. The formulations can be so constituted that they release the active ingredient only or preferably in a particular part of the intestinal tract, possibly over a period of time. The coatings, envelopes, and protective matrices may be made, for example, from polymeric substances or waxes.

The particular dosage of a compound of formula I required to inhibit the effects of growth hormone according to this invention will depend upon the severity of the condition, the route of administration, and related factors that will be decided by the attending physician. Generally, accepted and effective daily doses will be from about 0.1 to about 1000 mg/day, and more typically from about 50 to about 200 mg/day. Such dosages will be administered to a subject in need thereof from once to about three times each day, or more often as needed to effectively treat the syndrome or at least one of its symptoms.

It is usually preferred to administer a compound of formula I in the form of an acid addition salt, as is customary in the administration of pharmaceuticals bearing a basic group, such as the piperidino ring. It is also advantageous to administer such a compound by the oral route. For such purposes the following oral dosage forms are available.

Formulations

In the formulations which follow, "Active ingredient" means a compound of formula I.

    ______________________________________     Formulation 1: Gelatin capsules     Hard gelatin capsules are prepared using the following:     Ingredient        Quantity (mg/capsule)     ______________________________________     Active ingredient 0.1-1000     Starch, NF        0-650     Starch flowable powder                       0-650     Silicone fluid 350 centistokes                       0-15     ______________________________________

The ingredients are blended, passed through a No. 45 mesh U.S. sieve, and filled into hard gelatin capsules.

Examples of specific capsule formulations of raloxifene that have been made include those shown below:

    ______________________________________     Ingredient        Quantity (mg/capsule)     ______________________________________     Formulation 2: Raloxifene capsule     Raloxifene        1     Starch, NF        112     Starch flowable powder                       225.3     Silicone fluid 350 centistokes                       1.7     ______________________________________     Formulation 3: Raloxifene capsule     Raloxifene        5     Starch, NF        108     Starch flowable powder                       225.3     Silicone fluid 350 centistokes                       1.7     ______________________________________     Formulation 4: Raloxifene capsule     Raloxifene        10     Starch, NF        103     Starch flowable powder                       225.3     Silicone fluid 350 centistokes                       1.7     ______________________________________     Formulation 5: Raloxifene capsule     Raloxifene        50     Starch, NF        150     Starch flowable powder                       397     Silicone fluid 350 centistokes                       3.0     ______________________________________

The specific formulations above may be changed in compliance with the reasonable variations provided.

A tablet formulation is prepared using the ingredients below:

    ______________________________________     Formulation 6: Tablets     Ingredient        Quantity (mg/tablet)     ______________________________________     Active ingredient 0.1-1000     Cellulose, microcrystalline                       0-650     Silicon dioxide, fumed                       0-650     Stearate acid     0-15     ______________________________________

The components are blended and compressed to form tablets.

Alternatively, tablets each containing 0.1-1000 mg of active ingredient are made up as follows:

    ______________________________________     Formulation 7: Tablets     Ingredient          Quantity (mq/tablet)     ______________________________________     Active ingredient   0.1-1000     Starch              45     Cellulose, microcrystalline                         35     Polyvinylpyrrolidone                         4     (as 10% solution in water)     Sodium carboxymethyl cellulose                         4.5     Magnesium steardte  0.5     Talc                1     ______________________________________

The active ingredient, starch, and cellulose are passed through a No. 45 mesh U.S. sieve and mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant powders which are then passed through a No. 14 mesh U.S. sieve. The granules so produced are dried at 50°-60° C. and passed through a No. 18 mesh U.S. sieve. The sodium carboxymethyl starch, magnesium stearate, and talc, previously passed through a No. 60 U.S. sieve, are then added to the granules which, after mixing, are compressed on a tablet machine to yield tablets.

Suspensions each containing 0.1-1000 mg of medicament per 5 mL dose are made as follows:

    ______________________________________     Formulation 8: Suspensions     Ingredient             Quantity (mg/5 ml)     ______________________________________     Active ingredient      0.1-1000 mg     Sodium carboxymethyl cellulose                            50       mg     Syrup                  1.25     mg     Benzoic acid solution  0.10     mL     Flavor                 q.v.     Color                  q.v.     Purified water to      5        mL     ______________________________________

The medicament is passed through a No. 45 mesh U.S. sieve and mixed with the sodium carboxymethyl cellulose and syrup to form a smooth paste. The benzoic acid solution, flavor, and color are diluted with some of the water and added, with stirring. Sufficient water is then added to produce the required volume.

TEST PROCEDURE

Five to thirty healthy, late pubertal males are selected for the clinical study. The males are at Tanner genital stage IV or V, with testicular volumes≧15 mL. The growth hormone concentrations are determined, as well as concentrations of other hormones. The study has a placebo control group, i.e., the males are divided into two groups, one of which receives the active agent of this invention and the other receives a placebo. Males in the test group receive between 50-600 mg of the active agent per day by the oral rotate. They continue this therapy for 3-6 months. Accurate records are kept as to the concentrations of growth hormone and other hormones in both groups and at the end of the study these results are compared. The results are compared both between members of each group and also the results for each patient are compared to the concentrations reported by each patient before the study began.

Utility of the compounds of the invention is illustrated by the impact they have on the concentration of growth hormone when used in a study as above. 

We claim:
 1. A method of inhibiting the effects of growth hormone comprising administering to a human in need thereof an effective amount of a compound having the formula ##STR5## wherein R¹ and R³ are independently hydrogen, --CH₃, ##STR6## wherein Ar is optionally substituted phenyl; R² is selected from the group consisting of pyrrolidine, hexamethylenemino, and piperidino; or a pharmaceutically acceptable salt of solvate thereof.
 2. The method of claim 1 wherein said compound is the hydrochloride salt thereof.
 3. The method of claim 1 wherein said compound is ##STR7## or its hydrochloride salt.
 4. The method of claim 1 wherein said effects are gigantism or acromegaly. 